旋转往复板推进器诱导流场特性研究
The present study deals with the ow eld in the circular cross section of a cylindrical vessel induced by a rotationallyreciprocating impeller, rotating back and forth with gradual change in rotational speed. A periodically stable velocityeld was measured by PIV and also simulated by CFD. It was revealed that the velocity eld near the liquid free surfaceis basically 2-dimensional, except for the acceleration period at Re43, and agrees well with 2-dimensional CFD simulation,except for the development process of 3-dimensional tip vortices at Re43. The separation behavior of the vorticesoriginally generated at the impeller tip changed with increasing Reynolds number. No separation was observed at alower Reynolds number, while the separated vortices turn into 3-dimensional potential vortices and remain as 2-dimensionalvortices at the next impeller counterturn at higher Reynolds numbers. The uctuation of each velocity componentwas remarkably small, suggesting that the ow eld even at the highest Reynolds number was still laminar. It is foundthat eective transportation of energy from the impeller to 3-dimensional potential vortex is related to a large and constantpower number, which is reported in our recent publication.